Radial printing system and methods

ABSTRACT

Method and apparatus for receiving an image source representative of an image to be printed on an outer surface of a rotating media is described. The image source has a plurality of image points. A radial printing system is described that includes an imaging system configured to convert the plurality of image points into a polar-based representation of the image and a head assembly coupled to the imaging system for outputting the polar-based representation of the image onto the rotating media. The rotating media may represent a compact disk, wherein an inner surface of the compact disk is configured to store digital data

BACKGROUND OF THE INVENTION

[0001] The present invention relates to the manufacture of printingsystems and methods for printing. More particularly, the presentinvention relates to a printing system that is configured to radiallyprint onto a media that rotates in relation to a printing assembly.

[0002] Conventional printing systems typically utilize rectangular basedbitmaps. In general, a conventional printing system prints onto astandard size rectangular-shaped media along a horizontal axis, forexample, and the media is moved along a vertical axis. Typically, afterthe paper advances to a desired vertical location under a head assembly,the printing assembly moves across the paper to print an image onto thepaper while the paper is held stationary. In sum, conventional printingsystems generally implement movements within a rectangular coordinatesystem for printing onto media having standard sizes and shapes.

[0003] To facilitate discussion, FIG. 1 depicts a conventional printingsystem 10 in the form of a typical ink jet printer. As shown, theprinting system 10 includes a print head 102, a roller 106, and anactuator 108. The print head 102 is configured for dispensing ink onto aprint media 100, representing, for example, a rectangular sheet ofpaper. The actuator 108 is configured for moving the print head 102across the print media 100. The roller 106 is configured for moving theprint media 100 under the print head 102.

[0004] Typically, the roller 106 moves the print media 100perpendicularly to the movement of the print head 102. That is, themedia 100 travels under the print head 102 along a y-axis 110, and theprint head moves over the media 100 along a x-axis 112.

[0005] The movements of the roller 106 and print head 102 generallyoccur during different time periods. For example, the roller 106initially feeds the media 100 to an initial position under the printhead 102. This initial position is typically at the top, left comer ofthe media 100. The roller 106 stops moving the media 100, and the media100 is immobilized. After the media 100 stops moving, the print head 102begins to dispense ink across the media 100 at a first y-axis position.For conventional bi-directional printers, the print head 102 moves andprints from the left side to the right side of the media. When the printhead 102 reaches the right side of the media 100, the print head 102typically stops while the roller 106 moves the media 100 to a secondposition along the y-axis 110. For example, when the print head 106completes a first line, the roller 106 moves the media 100 up so thatthe print head 102 may then print a second line. After the roller 106repositions the media 100, the print head 102 moves and prints from theright side to the left side of the media 100 at a second y-axisposition.

[0006] Although conventional printing systems such as those describedabove are suitable for certain applications, they also have certaindisadvantages. For example, since the print head 102, in bi-directionalprinters, moves and prints from left to right and then from right toleft, the timing of the ink dispensement is relatively complex. That is,when the print head 102 is moving in the +x direction, ink must bedropped at a position to the left of the desired ink dispensement siteon the media 100. In contrast, when the print head 102 is moving in the-x direction, ink must be dropped at a position to the right of thedesired ink dispensement site on the media 100.

[0007] Also, if odd-shaped, or non-rectangular, media 100 were placedwithin a conventional rectangular based printer, the print head 102 andassociated actuator 108 would necessarily be configured such that spacewas wasted. For example, for a CD-shaped media 100, the actuator 108would have to be configured to allow printing across the full diameterof the CD. That is, the actuator 108 would necessarily move the printhead across the entire diameter of the CD. In other words, theconventional printer will be configured to print within a rectangulararea that encompasses the CD-shaped media. In sum, the actuator 108 ofthe conventional printer 100 is necessarily configured to print linesacross a maximum width of the media 100. Consequently, the size of theactuator 108 in typical rectangular based printers must typically beconfigured to move the print head along a maximum width of the media100.

[0008] Conventional printing systems 10 fail to provide an easy way forprinting on non-standard size media, such as a label for a CD-ROM 104shown in FIG. 1. Being circular in shape and too small and/or irregularin size to be properly handled by the paper handling system ofconventional printer systems, the CD label must typically be attached insome manner to another regular-sized media (e.g., a sheet of paper) andfed as such into the conventional printer before printing can occur.Conventionally printing systems are also typically not able to handleinflexible media types, such as a CD itself, for example. Even forprinters that do not require flexible media, one must typically add aspecial media holder for each type of non-standard media. Otherwise, thenon-rectangular shape of the CD label causes difficulties inconventional printing systems, which are typically configured to handlemedia and print head movements in the rectangular system. Also, printingcontrol systems (not shown), which control the movements of the printhead 102, typically are not designed to direct the print head acrossmedia (e.g., 102) having variable widths along the x-axis 112, such asthe circular-shaped CD label 104 of FIG. 1.

[0009] Conventional printers also fail to efficiently utilize allmovements of the media 100 for printing. That is, the print head 102stops dispensing ink onto the media 100, i.e., stops printing as theroller repositions the media 100. Thus, during operation of conventionalprinters, there may be a period of time during which no printing occurs.

[0010] In view of the foregoing, there is a need for an improvedprinting system, and more specifically, an improved printing system thatefficiently implements simple movements for printing onto media havingnonstandard size and shape.

SUMMARY OF THE INVENTION

[0011] To achieve the foregoing and other objects and according to thepurpose of the present invention, a radial printing system for receivingan image source representative of an image to be printed on an outersurface of a rotating media is disclosed. The image source has aplurality of image points.

[0012] In one embodiment, the radial printing system includes an imagingsystem configured to convert the plurality of image points into apolar-based representation of the image and a head assembly coupled tothe imaging system for outputting the polar-based representation of theimage onto the rotating media. In an alternative embodiment, therotating media represents a compact disk, wherein an inner surface ofthe compact disk is configured to store digital data.

[0013] In another embodiment, the radial printing system includes animaging system configured to provide a print position look-up tablehaving therein print position representations of the image points toprint the representation of the image source onto the rotating media.The imaging system is also configured to obtain one of the printposition representations from the print position look-up table for atleast some of the image points of the image source. The radial printingsystem further includes a head assembly coupled to the imaging systemfor outputting the representation of the image source onto the rotatingmedia based on the obtained print position representations of the imagepoints.

[0014] In yet another embodiment, the radial printing system includes animaging system configured to receive the image source and to associateindividual data of the image points with respective ones of the inkdispensement areas on the platter within a rectangular address look-uptable such that the representation of the image source may be printedonto the rotating media by the head assembly and a head assembly coupledto the imaging system for outputting the representation of the imagesource onto the respective ink dispensement areas of the rotating mediabased on the rectangular address look-up table.

[0015] The radial printer may further include a rotation motorconfigured to rotate the media and to provide rotation position datathat indicates a current rotation position of the rotation motor and aservo system configured to receive the rotation position data from therotation motor and to control the rotation motor responsive to therotation position data.

[0016] In yet another embodiment, the radial printing system includes aplatter for supporting the rotating media, a head assembly disposedabove the platter for printing onto the rotating media, a rotation motorfor rotating the platter, a servo system configured for controlling therotation motor, and an imaging system coupled to the head assembly andconfigured to receive the image source and to associate each point onthe representation of the image source to a particular ink dispensementarea on the rotating media such that the image source may be printedonto the rotating media by the head assembly. The imaging system isfurther configured to reduce printing distortion that arises frommatching the image points with respective ones of the ink dispensementareas and/or from a rotational motion of the rotating media.

[0017] In another embodiment, a method for reproducing an image on anouter surface of a rotating media is disclosed. Data representing theimage is received. The data representing the image is converted into apolar-based representation of the image. A reproduction of the image onthe rotating media is printed, using the polar-based representation ofthe image.

[0018] By way of another embodiment, the media is rotated in asubstantially continuous manner. A rectangular based bitmap is received.The rectangular based bitmap has a plurality of rectangular data points,wherein each rectangular data point represents at least an associatedone of the image data points of the image source. A first rectangulardata point is obtained from the rectangular based bitmap. A printposition look-up table that has print position representations for atleast some of the plurality of rectangular data points is provided. Oneof the print position representations for the first rectangular datapoint from the print position look-up table is obtained and furnished tothe printing mechanism such that the printing mechanism may reproducethe first rectangular data point onto the rotating media based on theposition data. The subsequent data points are similarly reproduced ontothe rotating media to form a copy of the image source on the rotatingmedia. The printing is performed with a printing mechanism that printsradially relative to the rotating media.

[0019] In an alternative embodiment, a method for reproducing an imageon outer surfaces of a plurality of rotating media is disclosed. Theplurality of rotating media are simultaneously disposed on a rotatingplatter of a radial printing system. Data representing the image isreceived and converted into a polar-based representation of the image. Aportion of a reproduction of the image is printed on the plurality ofrotating media during a given rotation of the rotating platter by usingthe polar-based representation of the image.

BRIEF DESCRIPTION OF THE DRAWINGS

[0020] The present invention is illustrated by way of example, and notby way of limitation, in the figures of the accompanying drawings and inwhich like reference numerals refer to similar elements and in which:

[0021]FIG. 1 represents a conventional printing system.

[0022]FIG. 2 is a diagrammatic representation of a radial printingsystem in accordance with one embodiment of the present invention.

[0023]FIG. 3 is a diagrammatic representation of the head assembly ofFIG. 2 in accordance with one embodiment of the present invention.

[0024]FIG. 4 is a diagrammatic representation of connections to and fromthe servo system of FIG. 2 in accordance with one embodiment of thepresent invention.

[0025]FIG. 5 is a diagrammatic representation of an imaging system ofFIG. 2 in accordance with one embodiment of the present invention.

[0026]FIG. 6 is a flowchart illustrating the process of converting arectangular based bitmap into a polar based bitmap to facilitate radialprinting in accordance with one embodiment of the present invention.

[0027]FIG. 7 is a diagrammatic representation of wide-swath, radialdependent distortion.

[0028]FIG. 8 is a diagrammatic representation of mismatches betweenimage points and printing points along quantized angles.

[0029]FIG. 9 is a diagrammatic representation of twisting distortion 900on a CD, for example.

[0030]FIG. 10 is a diagrammatic representation of a character “A” thathas been converted into a plurality of rectangular dots and plurality ofpolar dots.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0031] The present invention will now be described in detail withreference to a few preferred embodiments as illustrated in theaccompanying drawings. In the following description, numerous specificdetails are set forth in order to provide a thorough understanding ofthe present invention. It will be apparent, however, to one skilled inthe art, that the present invention may be practiced without some or allof these specific details. In other instances, well known process stepsand/or structures have not been described in detail in order to notunnecessarily obscure the present invention.

[0032] In accordance with one aspect of the present invention, theprinting system is configured to print radially onto a rotating mediathat may have a nonstandard shape or size, such as a label for a CD orthe CD itself. The present invention takes advantage of rotationalmovement of the media to facilitate efficient printing. In oneembodiment, the media continuously rotates below a head assembly as thehead assembly radially dispenses ink onto the print media. The printhead may be configured to incrementally move and print along a radialline with respect to the rotating media as the media rotates. In oneembodiment, printing is continuous as the media rotates below the printhead, which results in more efficient printing, in contrast toconventional printers. The printing system may also be configured toconvert a rectangular based bitmap into a polar based bitmap tofacilitate radial printing on the rotating media.

[0033]FIG. 2 is a diagrammatic representation of a radial printingsystem 200 in accordance with one embodiment of the present invention.As shown, the radial printing system includes a platter 201, a headassembly 210, an imaging system 202, a rotation motor 208, a servosystem 206, and a synchronization system 204.

[0034] The platter 201 represents a mechanism for supporting the media220. Alternatively, the platter 201 itself may function as the media 220upon which the head assembly 210 dispenses ink. In one embodiment, theplatter 201 may also include a holding device for affixing the media 220onto the platter 201. The holding device may be in any suitable form forattaching the particular type of media (e.g., 220) to the platter 201.For example, the holding device may include a vacuum, electrostatic,magnetic, or adhesive device depending on the type of media that isbeing attached to the platter 201. Preferably, when the media is in theform of a CD, a magnetic holding device is implemented. By way ofexample, a clamping mechanism utilizing magnetic clamping may beemployed to trap and hold the CD to the platter surface. Additionally,the holding device may be configured to attach a plurality of media tothe platter 201 at one time. For example, the platter 201 may have aplurality of regions, wherein each region implements a holding devicefor holding one sheet of paper or a CD. Alternatively, a single holdingdevice may be employed to hold the multiple media on the platter 201.

[0035] The platter 201 and/or holding device are configured toaccommodate media of various shapes and sizes. For example, the mediamay be disc-shaped, odd-shaped, flexible, rigid, thick, or thin; themedia may be in the form of cardboard, paper, ceramic tiles, plastics,metals, textiles, wood, or leather. Specifically, the media may be inthe form of a label for a CD, or the CD itself, that covers most of theplatter surface or a small sheet of paper (220) that covers a smallportion of the platter surface. These media examples are merelyillustrative, and are not meant to limit the scope of the presentinvention.

[0036] The head assembly 210 represents a mechanism for, among otherthings, radially printing onto the media 220 as the platter 201 rotatesto bring the printable regions of the media 220 to a position directlybelow the head assembly 210. As previously mentioned, the platter 201may be configured, in one embodiment, to rotate continuously whileprinting takes place. This configuration is in sharp contrast withconventional printing systems, wherein media movement typically ceasesaltogether while printing takes place.

[0037] The head assembly 210 may also be configured to move along aradial direction 212 from the inner diameter (ID) to the outer diameter(OD), and/or vice versa, while the media 220 rotates in a circulardirection 214 that may be either counter clockwise or clockwise. Oneembodiment of the head assembly 210 is further described below inreference to FIG. 3.

[0038] The rotation motor 208 represents a mechanism for rotating theplatter 201 (and the media 220) along a circular direction 214. Therotation motor 208 is in the form of any suitable motor for rotating aplatter. For example, the rotation motor 208 may be in the form of astand alone stepper and/or encoder motor and/or a brushless DC and/orTach loop and/or angle encoder. Alternatively, the rotation motor 208may be implemented by an existing OEM platter rotation motor that mayserve other non-printing related functions. For example, the presentinvention may be configured to utilize a rotation motor from an existingCD-R writer device or CD player. In one particularly advantageousembodiment, the present invention may even be integrated into an OEMdevice, such as a CD-R writer device to take advantage of the existingmotor therein.

[0039] The servo system 206 represents a mechanism for controlling,among other things, the rotation of the rotation motor 208. Tofacilitate control of the rotation motor 208, the servo system 206 mayreceive rotation data from the rotation motor 208 that tracks a rotationposition of the rotation motor 208 and/or platter 201. The rotation datamay be in the form of encoder data from the rotation motor 208. Based onthe position data, the servo system 206 outputs control data to therotation motor 208. For example, the position of the rotation motor 208may be detected and sent as encoder data to the servo system 208. Theservo system 208 then adjusts the rotation position of the rotationmotor 208 based on the encoder data. Thus, the servo system 206 may beemployed to control the rotational speed of the rotation motor 208.

[0040] The servo system 206 may also control movement of the headassembly 210, as well as rotation of the rotation motor 208.Specifically, the servo system 206 may be configured to move the headassembly 210 to a particular position along a radial axis 212. Oneembodiment of the servo system 206 is further described below inreference to FIG. 4.

[0041] The imaging system 202 represents a mechanism for controllingwhen the head assembly 210 initiates and terminates printing aparticular dot, swath, strip, or pattern that forms part of the image tobe reproduced onto the media 220 as the head assembly traversesdifferent areas of the media. The imaging system signals when todispense the ink, for example, onto the media 220 such that a particulardot is printed onto the media 220 at a particular position. The imagingsystem 202 receives, analyzes, and transforms an image source 216 todetermine how to control the head assembly 210. To facilitate printingonto the rotating media 220, the imaging system 202 may be configured,among other things, to convert a rectangular based bitmap into a polarbased bitmap. One embodiment of the imaging system 202 is furtherdescribed below in reference to FIG. 5.

[0042] The synchronization system 204 represents the mechanism forcoordinating the functions of the imaging system 202 and the servosystem 206 such that the head assembly 210 printing occurs at a specificposition on the media 220. That is, the synchronization system 204 tellsthe head assembly 210 when and where to deposit a particular dot of theimage source 216 onto the media 220. The synchronization system 204 mayalso be configured to coordinate the movements of the rotation motor 208and/or head assembly 210 with the timing of the printing of theparticular dot.

[0043] In an exemplary configuration, the head assembly 210 ispositioned over the platter 201. The rotation motor 208 is coupled withthe platter and the servo system 206. The servo system 206 is alsocoupled with the head assembly 210. The synchronization system 204 iscoupled with the imaging system 202 and the servo system 206, and theimaging system 202 receives the imaging source 216.

[0044] The radial printing system 200 may be in the form of a devicethat is external to and coupled with a computer system. That is, theradial printing system 200 may be packaged separately or integrated intosome other device, such as a conventional CD-R writing device.Preferably, if the radial printing system 200 is implemented into aconventional CD writing device, the CD also functions as the platter 201during CD printing, as well as during conventional CD writing. If theradial printing system 200 is packaged separately, the radial printingsystem may also include a data input device, such as a floppy drive, toreceive the image source 216. Alternatively, the radial printing system200 may be integrated into a computer system as a peripheral device.

[0045] The radial printing system 200 may also include a media feedingdevice (not shown) for handling a plurality of media 220. The mediafeeding device may be in any form that is suitable for handling theparticular type of media and that is suitable for the particularprinting application. For example, for home use, a card stacker andfeeder may be implemented as a media feeding device. Alternatively, aconventional CD tray may be used if the present invention is integratedinto a CD writing device (i.e., of binary data onto the computerreadable medium). The media feeding device may feed more than one pieceof media onto the holding device of the platter 201 at one time so thatmultiple pieces of media may be simultaneously printed onto the platter.

[0046]FIG. 3 is a diagrammatic representation of the head assembly 210of FIG. 2 in accordance with one embodiment of the present invention.The head assembly 210 may be configured in any form that is suitable forprinting onto a media. For example, the head assembly may implement inkjet, laser, pen, dye-sublimation, thermal transfer, electrostatic,impact, or offset printing technologies. By way of another example, thehead assembly may implement digital duplication technologies, whereinthe head assembly includes a master roller to duplicate an image onto aplurality of media. These types of printing technologies are well knownin the art. By way of another example, the head assembly 210 may beconfigured to facilitate a chemical vapor deposition, photolithography,or electron beam writing process on a semiconductor wafer (e.g., whenthe media is a semiconductor wafer). Alternatively, the head assembly210 may be configured to deposit a first chemical onto a media having asecond chemical such that the first chemical reacts with the secondchemical, resulting in a third chemical being formed on the media. Insum, the head assembly 210 may be configured in any form that issuitable for printing or forming a desired pattern of any type ofmaterial onto any type of media.

[0047] As shown, the head assembly implements ink jet technology. Thehead assembly 210 includes a print head 302 having a nozzle array 304,an actuator 306, a translational motor 308, and a support rail 316.

[0048] The print head 302 is in the form of a conventional ink jetcartridge. The print head 302 represents a mechanism for controlling thenozzle array 304, and the nozzle array 304 represents a mechanism fordispensing ink onto the media. The nozzle array 304 has one or more inkdispensers that are configured to print onto the media at a particularradial area, or swath as the media rotates underneath. For example, thenozzle array 304 may cover only a portion of the entire radial dimensionbetween ID and OD of the platter 201. To print onto different areas ofthe media, the print head may be controlled to move radially as themedia rotates. Alternatively, the nozzle area may even cover the entireradial dimension, thereby being capable of simultaneously printing atevery point along a particular radius of the platter 201 (e.g., 314).

[0049] The print head 302 may be configured to receive a head controlsignal 312 that is output from the imaging system (e.g., 202 of FIG. 2).The head control signal 312 directs the flow of ink onto the media. Oneembodiment of the imaging system 202 and the head control signal 312 arefurther described below in reference to FIG. 5.

[0050] The head assembly 210 may implement any suitable means forradially moving the print head 302 across the rotating media. Of course,it may not be necessary to move the print head 302 if the nozzle array304 of the print head 302 spans across the radial dimension of theplatter 201 that substantially includes the entire desired radialprinting area of the media 220. For example, if the nozzle array 302spans over a radial area between ID and OD (e.g., 314), the headassembly 210 is capable of simultaneously printing along an entireradius of the media 220 on the platter 201. The fact that no mechanicalmovement of the print head 302 is required along the radial directionrenders the system substantially more reliable and also improves thespeed at which printing may be accomplished (since the swath is larger).In contrast, if the nozzle array 304 is not configured to simultaneouslyprint along an entire radius of the desired printing area of the media220, the print head 302 may be configured to radially move to anyposition between ID and OD.

[0051] Depending on the requirements of the particular application, itmay be desirable to configure the head assembly 210 such that the head'sradial movement is restricted. For example, for printing onto a CD, thehead assembly 210 may be configured to not allow printing within theinner grooved section of the CD since it may be difficult to print onthis section.

[0052] The actuator 306 and translational motor 308 represent mechanismsfor radially moving the print head 302. Of course, an actuator and motorare not required if the head assembly spans the full radius of theplatter or spans the entire portion of the radius that represents theprintable area. The actuator and motor may be in any suitable form forradially moving the print head 302 across the platter 201. For example,the actuator 306 and translational motor 308 may be in the form of,among others, a screw drive and stepper motor, linear drive withfeedback position, or band actuator and stepper motor.

[0053] As shown, the print head 302 is slidably coupled with actuator306, which actuator 306 is coupled with the translational motor 308. Theactuator 306 is supported by the support rail 316. Specifically, theactuator 306 represents a mechanism for radially moving the print head302, and the translational motor 308 represents a mechanism forproviding power to the actuator 306. As shown, the actuator 306 is inthe form of a screw drive that is coupled with a translational motor 308that is in the form of a stepper motor. Basically, each turn of thetranslational motor 308 moves the actuator 306, which, in turn, movesthe print head 302 to a particular radial position between ID and OD.

[0054] The translational motor 308 is configured to receive a headcontrol signal 310 from the servo system 206 and to output a headposition signal 310 to the servo system 206. The head control signal 310controls the position of the translational motor 308, and the headposition signal 310 indicates the position of the translational motor308 and corresponding position of the head assembly 210. One embodimentof the servo system 206 is further described below in reference to FIG.4. Alternatively, the present invention may utilize motor controlsignals from an existing OEM device, such as a CD R-writer.

[0055] In an alternative embodiment, the head assembly 210 may include acuring bar for curing ink or a drying bar for drying ink. One or bothtypes of bars (not shown) may be positioned over the platter 201. Forexample, if UV curable ink is used, a curing bar may be configured overthe media 220 to cure the ink as it is deposited onto the media 220 bythe nozzle array 304. By way of another example, the curing bar may bein the form of a fuser for fusing ink that is deposited by a laser typehead assembly, for example, onto the media 220.

[0056] In another alternative embodiment, the head assembly 210 may alsoinclude an optical reader that represents a mechanism for obtainingoptical information from the platter 201 and/or media 210. The presentinvention may incorporate an optical reader from an existing OEM device,such as a CD R-writer, or may be integrated into a separate radialprinter package. For example, the optical reader may be configured toscan a first printed image from the media 210 and output the firstprinted image in the form of an optical feedback signal to the imagingsystem 202. The first printed image may then be manipulated to create,for example, a second image that is different than the first image andto output the second image to the imaging system 202 in the form of anew image source 216. The second image may then be printed over thefirst image of the media 220. Alternatively, the first printed image maybe printed onto another media 210. For example, the optical reader mayscan and read a master image from a master CD and output the masterimage to the imaging system 202. The master image may then be duplicatedon a plurality of other CD's. Advantageously, the radial printing systemfunctions as a copier for irregular shaped media, and particularly, as ahigh speed copier if multiple pieces of media are arranged to be printedper rotation of the platter.

[0057] Alternatively, the optical reader may be configured to recognizea mark on the media 210 or the platter 201 to determine a referencepoint on the platter 201. For example, a particular mark on the platter201 will indicate the zero angle radius of the platter 201. Thereference point of the platter 201 may then be defined as a point on theplatter 201 that is positioned at the zero angle radius and at an innerdiameter (ID) of the platter 201. The reference point of the platter 201corresponds to a reference point within the image source 216. Likewise,each point in the image source 216 may then be matched with a particularpoint on the platter, wherein each image source point is in reference tothe reference point of the image source 216 and the platter 201. Thisreference point determination process is further described below inreference to FIG. 6.

[0058]FIG. 4 is a diagrammatic representation of connections to and fromthe servo system 206 of FIG. 2 in accordance with one embodiment of thepresent invention. The servo system 206 represents a mechanism forcontrolling movement within the radial printing system 200. That is, theservo system 206 controls mechanical motors within the radial printingsystem 200.

[0059] As shown, the servo system 206 is configured to receive rotationposition data 414 from the rotation motor 208. The rotation positiondata 414 indicates a current rotation position of the platter 201. Theservo system 206 then analyzes the rotation position data 414 andoutputs a rotation control signal 406 to adjust the rotation position ofthe platter 201 in response to the rotation position data 414.

[0060] The servo system 206 may provide a substantially constant linearrotation speed or a substantially constant angular velocity. A constantlinear rotation speed may result in simplified printing control.Alternatively, the servo system 206 may provide a constant angularvelocity or variable velocity. However, printing control may be morecomplex to compensate for distortions that may occur due to differentlinear velocities at different radii, which distortion is describedbelow.

[0061] The servo system 206 may also be configured to receive headposition data 412 from the head assembly 210. The head position data 412indicates a current head position of the print head 302 of the headassembly 210. The servo system 206 then analyzes the head position data412 and outputs a head control signal 408 to the head assembly 210. Thehead control signal 408 adjusts the radial position of the head assembly210 in response to the head position data 412. Of course, as discussedabove, the head assembly 210 may not necessarily be configured forradial movement. In which case, the head assembly 210 would only becontrolled by the imaging system 202 and not by the servo system 206.Alternatively, the servo system 206 may be configured to move theplatter 201 relative to the head assembly 210.

[0062] The servo system 206 may also be configured to receive an opticalfeedback signal 418 from an optical reader 401. For example, the opticalreader 401 may be implemented to provide optical sensing and recognitionof the media 220, such as the position and shape of the media 220. Byway of another example, the optical reader 401 may scan the printedimage from the media 220 and output the scanned image to the computersystem so as to enable a user to view and/or manipulate the scannedimage. It may then be possible to print another image, or a duplicateimage, over the media 220.

[0063] The servo system 206 may also be configured to receive verticalposition data 416 from a Z-motion control block 402 that moves the headassembly 210 along a vertical axis. The vertical position data 416indicates a current vertical position of the head assembly 210. Theservo system 206 then analyzes the vertical position data 416 andoutputs a vertical control signal 410 to adjust the vertical position ofthe head assembly 210 in response to the vertical position data 416. Anysuitable technologies may be implemented for detecting the verticalposition, such as audio, mechanical, or optical sensors, andrepositioning the head assembly 210 along the Z-axis. Of course, theZ-motion control block 402 is optional and may be quite useful forcertain applications, such as three-dimensional or unusually thick media220. Alternatively, the servo system 206 may be configured to verticallymove the platter 201 relative to the head assembly 210.

[0064] The servo system 206 may also be configured to receive asynchronization signal 420 from the synchronization system 204. Forexample, the synchronization signal 420 may control the timing of thehead control signal 408 that radially moves the print head 302, and maycontrol the timing of the rotation control signal 406 that rotates theplatter 201. It may be necessary to control the movement of the printhead 302 and platter 201 to facilitate the depositing of ink at aparticular location on the media 220 and platter 201.

[0065] The servo system 206 may be implemented as a stand alone deviceor integrated within a computer system. For example, the servo system206 may be implemented on a peripheral board within the computer system,which board is configured to receive encoder signals from the rotationmotor 208 and head assembly 210 and transmit control signals from theservo system 206. Additionally, the servo system 206 may be implementedin software, hardware, or firmware.

[0066]FIG. 5 is a diagrammatic representation of an imaging system 202of FIG. 2 in accordance with one embodiment of the present invention.The imaging system 202 includes a computer system 512 having anapplication program 510, a raster image processor 502, a rectangular topolar block 504, a buffer 506, and a firing control block 508.

[0067] Basically, the imaging system 202 converts an image source fromthe application program 510 of the computer system 512 into a set ofpolar based data points 522. The polar based data points 522 may then beused by a firing control block 508 for controlling the flow of ink fromthe head assembly 410. In other words, each polar based data pointcorresponds to a particular position on the platter 201. Thus, aparticular polar based data point may be used to print at acorresponding position of the platter 201, which position corresponds toa specific ink dispensement area on the media 220.

[0068] Although most of the components of the imaging system 202 aredescribed as being separate from the computer system 512, in otherembodiments, some or all of these components may be integrated into thecomputer system 512. Additionally, in other embodiments, the componentsof the imaging system 202 may be separate components or integrated intoone or more devices. In additional embodiments, the components of theimaging system 202 may be configured in alternative ways, such asswapping the rectangular to polar block 504 with the buffer 506.

[0069] The imaging system 202 may include the computer system 512 thathas a computer application program 510 for generating and outputting animage 516. Of course, if the components of the imaging system wereintegrated in a computer system, there would be no need for the separatecomputer system 512. The image may be written in any suitable printingdescription language. Several well known printing description languagesare QuickDraw, PostScript, or PCL.

[0070] The raster image processor (RIP) 502 is configured to convert theimage 516 into a rectangular based bitmap 518. The rectangular basedbitmap 518 includes an array of data points that are referenced by x-ycoordinates. Most conventional printing systems use the rectangularbased bitmap 518 to control printing. However, rectangular to polarblock 504 provides a mechanism for converting the rectangular basedbitmap 518 into a polar based bitmap to facilitate printing onto arotating platter 201. The rectangular to polar block 504 also providesdistortion correction for reducing distortion in the printed image. Twoexamples of image distortion problems are discussed below in referenceto FIGS. 7 and 8. Additionally, a process for implementing theconversion function of the rectangular to polar block 504 are describedbelow in reference to FIG. 6.

[0071] The rectangular to polar block 504 may be configured to receivethe rectangular based bitmap 518 from the raster image processor 502.The rectangular to polar block 504 is also configured to convert datapoints of the rectangular based bitmap 518 into one or morecorresponding polar data points. The rectangular to polar block 504 mayalso be configured to arrange the polar data points into a polar basedbitmap 520 that is output to the buffer 506. Alternatively, therectangular to polar block 504 may be configured to provide a printposition look-up table for some or all of the rectangular data points.By way of another alternative, the rectangular to polar block 504 maynot be necessary when a rectangular address look-up table is providedfor each printing position on the platter 201. Both of thesealternatives are further described below in reference to FIG. 6.

[0072] The buffer 506 is configured to receive the polar based bitmap520 from the rectangular to polar block 504. The buffer 506 is alsoconfigured to arrange and/or order the polar data points of the polarbased bitmap 520 such that the firing control block 508 may access theordered data points 522 as needed for printing onto a particular inkdispensement area on the media 220. For example, the buffer 506 mayarrange the polar data points such that the firing block 506 may accessthe polar data points for printing in sectors, similar to printingtechniques employed for writing to a computer disk. In other words, thepolar data points are ordered such that a first sector is accessed andprinted, a second sector is then accessed and printed, etc. By way ofanother example, for printing one dot at a time, the buffer 506 mayorder the polar data points by angle of each particular radius such thateach data point is printed in ascending order.

[0073] Alternatively, the buffer 506 may be configured to arrange thepolar data points of the polar bitmap 520 into swaths. Each swath isdefined as a region that encircles the platter 201 and encloses aprintable area between two diameters, wherein the head assembly 210 iscapable of simultaneously printing a set of ink dispensement areas thatare positioned between the two diameters at a particular angle. Thus,the polar data points may be ordered into swath groups with the firstswath group being the innermost swath and the outermost swath being thelast swath group (or vice versa). Each swath group is ordered into anglegroups with the first group being the zero angle, and each angle groupis ordered by ascending order, for example, into a set of inkdispensement areas that are positioned between the two diameters of theswath at a particular angle. Thus, the head assembly 210 maysequentially print each set of ink dispensement areas within aparticular swath.

[0074] Although the RIP 502, rectangular to polar block 504, and buffer506 are described as being separate components from the computer system512, some or all of these components may be integrated into the computersystem 512. Additionally, these components (502, 504, and 506) may beimplemented in hardware, software, or both.

[0075] The firing control block 508 is typically integral to the headassembly 210. The firing control block 508 is configured to receive theordered data points 522 from the buffer 506 and to output an ink controlsignal 312 to the print head 302. The ink control signal 312 directs thetiming of the flow of ink that is output by the head assembly 210 ontothe media 220. The firing control block 508 may also be configured toreceive a synchronization signal 524 from the synchronization system204. The synchronization signal 524 may be used by the firing controlblock 508 to time the printing of a particular ink dispensement areaonto the media 220 such that the particular area is printed onto aparticular position on the media 220. In other words, thesynchronization system 204 coordinates the firing control block's inkcontrol signal 312 with the servo system's control signals (e.g., headcontrol signal and rotation control signal), which directs themechanical movement within the radial printing system 200.

[0076] The computer system 512 may also be configured to receive anoptical feedback signal 514 from an optical reader. The optical feedbacksignal 514 represents a scanned image that was obtained by the opticalreader. The optical feedback signal 514 may be used to facilitate imagemanipulation or changes within the computer application 510. Forexample, a user may overlay another image onto the scanned image, andthen output the combined image as the image source 516.

[0077]FIG. 6 is a flowchart illustrating a process 600 for converting arectangular based bitmap into a polar based bitmap to facilitate radialprinting in accordance with one embodiment of the present invention. Theprocess 600 may be implemented as rectangular to polar block 504 of FIG.5, for example. The rectangular bitmap represents an image source thatis output from a computer application program, for example, and is to beprinted onto a media.

[0078] Initially, in operation 602, a polar reference point is definedwithin the rectangular based bitmap, and this polar reference point ismapped to the reference point of the platter 201. The reference point ofthe platter corresponds to, for example, either the OD or the ID of theaxis of rotation of the platter 201 and to a selected radius that isdefined as having a zero angle or any arbitrary point along line 212.

[0079] The zero angle radius of the platter 201 is defined by anysuitable technique. For example, the zero angle radius may be defined asa particular radius on the platter 201 that is positioned below the headassembly when the rotation motor is at a particular rotation position.Alternatively, a mark on the media (e.g., a CD label) or the platter maydefine the zero angle radius. For example, an optical reader may beemployed to find the position of the mark and define the zero angleradius.

[0080] The polar reference point may be associated with any data pointwithin the rectangular bitmap. A reference rectangular data point thatis associated with the polar reference point may be chosen arbitrarilyor may be based on the size and shape of the image, as well as therequirements of the particular application of the present invention. Forexample, a rectangular image may be printed onto a rectangular shapedmedia that is offset from the center of the platter by choosing areference data point within the rectangular bitmap that iscorrespondingly offset from the rectangular image. By way of anotherexample, a circular image with a hole in the center may be printed ontoa circular shaped media by selecting a reference data point within therectangular bitmap that corresponds to the center of the hole.

[0081] By way of another example, the user may define a reference pointin the rectangular bitmap such that the entire image is printed onto aprintable area of the platter 201. Alternatively, the user may choosenot to print the center of the image by defining the reference point inthe rectangular bitmap as the center of the image such that part of theimage is not printed. In this example, the center portion of the imagemay not be printed since the reference point may not be within theprintable area.

[0082] Next, in operation 604, a rectangular based data point isobtained from the rectangular bitmap. Preferably, the rectangular datapoint is obtained in a some kind of logical order. For example, therectangular data point having the lowest x-value and the lowest y-valueis obtained first. The rectangular data point is then transformed intopolar notation in operation 606.

[0083] Any suitable method may be used for converting the rectangulardata point into one or more polar data point. That is, any method may beimplemented that converts a rectangular data point that is representedby x and y coordinates into one or more polar data point that isrepresented by radius and angle coordinates. The following expressionsare example operations for finding the radius (r) and angle (θ)coordinate of the rectangular data point:

r=(X ² +y ²)^(½)

θ=arccos (x/r)

[0084] By way of another example, θ may be calculated by arctan (y/x).The polar data point is then added to a polar bitmap (e.g., 506) inoperation 608. Operations 604 through 608 are then repeated for eachrectangular data point of the rectangular bitmap. After all therectangular data points are converted to polar data points and the polardata points are added to the polar bitmap, the polar bitmap is furnishedto the buffer (e.g., 506) in operation 610. The buffer may then beaccessed by the firing control block (e.g., 508) to print the imagesource onto the rotating media. Of course, each polar data point may beprinted prior to obtaining the next rectangular data point from therectangular bitmap (i.e., there may be no need, in one embodiment towait until the entire rectangular bitmap is transformed). Additionally,if more than one piece of media is attached to the platter 201, thepolar data points may be arranged in the polar bitmap to print anidentical image onto all media pieces, or to print different images ontothe media pieces (by appropriately referencing the polar reference pointto the rectangular reference point).

[0085] Preferably, a print position look-up table may be implemented tostore print positions on the platter, for example, corresponding to therectangular data points of the image. That is, the print positionlook-up table includes position data for representing a rectangular datapoint onto the platter 201. The print position look-up table may includeprint position data for all possible rectangular data points or for aportion of all possible rectangular data points, wherein simpleconversion calculations are used to obtain print position data fornon-stored rectangular data points based on stored position data. Forexample, print position data may be stored for one quadrant, and othernon-stored quadrant position data is obtained by simple reflectiontechniques. Of course, some rectangular data points may have no printedcounterparts for distortion correction purposes. Thus, during theprinting process, each rectangular data point does not have to beconverted into a polar data point. Instead, polar data is calculatedprior to printing and provided within the print position look-up table.During printing, print position data for each rectangular data point onthe platter 201 is obtained from the print position look-up table. Thistechnique requires less computations during the printing process thanthe previously described technique of FIG. 6 since a polar data point isnot generated for each rectangular data point.

[0086] Preferably, a rectangular address look-up table may be utilizedto store addresses of associated rectangular data (e.g., the color of anassociated dot) for each print position on the platter 201. Thus, priorto printing a particular dot or print area, the associated rectangulardata is obtained for the particular dot or print area by referencing therectangular address look-up table. In other words, the location of theassociated rectangular data in the rectangular bitmap is obtained fromthe rectangular address look-up table for each dot or print area, theassociated rectangular data is then obtained, and the associatedrectangular data is printed for the particular dot or print area. Thistechnique has the advantage of utilizing less storage space for the datapoints than the above embodiments since an image stored in rectangularnotation may be more compact than an image stored in polar notation.

[0087] Operation 606 may also include techniques for correcting printingdistortion that may occur in radial printing. For example, one type ofdistortion may occur when more than one dot is printed at one time ontoa radial line of the media. The dots of a first radial line will not allbe printed at a same distance from the dots of an adjacent second radialline. In other words, the outer dots of two adjacent printed lines arefarther apart than the inner dots because of a difference in linearvelocity between dots at different radii and the resulting timedifferences for the ink to reach different dots at different radii. Byway of example, for a wide swath that is positioned close to the originof the rotating platter, two printed lines may diverge such that a gapis present between the two printed lines.

[0088]FIG. 7 is a diagrammatic representation of this large swath,radial dependent distortion. As shown, a swath 714 that may be locatednear the innermost portion of the platter 201 has two printed lines 702and 704 that are separated by a radial dependent distance. As shown, adot 713 of printed line 702 is separated from a dot 712 of printed line704 by a distance 706, while a dot 718 of printed line 702 is separatedfrom a dot 720 of printed line 704 by a distance 708. The distance 706between the inner pair of dots is smaller than the distance 708 betweenthe outer pair of dots. This distortion tends to be less significant forswaths that are located on the outer portion of the platter or forswaths with narrow widths.

[0089] A second type of distortion occurs when some of the rectangulardata points of an image cannot match up to any of the available polarcoordinates. A limited number of polar data points may be availablesince the angles of the polar data points are typically represented bydigital values (e.g., quantized). In other words, the limited number ofpolar data points may fail to match up with all of the rectangular datapoints.

[0090]FIG. 8 is a diagrammatic representation of mismatches betweenrectangular data points and polar data points along quantized angles. Asshown, printed lines 814 and 816 are separated by a minimum predefinedangle 806 due to quantization. Because of the quantization of printangles, printed lines 814 and 816 cannot reference certain rectangulardata points. For example, rectangular data points 808, 810, and 812cannot be exactly matched to any polar data point along printed lines814 and 816. Thus, some estimations must be made to map theserectangular data points onto the printed lines 814 and 816. As shown,rectangular data point 808 is mapped onto polar data point 804 on printline 814, and rectangular data points 810 and 812 are both mapped ontopolar data point 802 on print line 816.

[0091] This “mismatch” distortion, as well as the “large swath”distortion, may result in a printed image that appears to includes aplurality of white spots or gaps that are inappropriately scatteredthroughout the printed image. More specifically, the “large swath”distortion may result in “pie-shaped” gaps within a portion of theprinted image that is located near the axis of rotation. If the numberof gaps or white spots within the printed image are significant, theywill likely detract from any other desirable characteristics of theprinted image and/or cause the printed image to not look right.

[0092] A third type of distortion that may occur in radial printing isreferred to as twisting distortion, which occurs when the ink isdeposited at points on the media having various linear velocities, forexample, when the media is rotated at a constant angular velocity. Forexample, for a CD the center of the disk is rotating at a slower linearvelocity than the outer edge of the CD. Thus, dispensing the ink at auniform rate results in a printed image that appears twisted within theinner portion of the image.

[0093]FIG. 9 is a diagrammatic representation of twisting distortion 900on a CD, for example. As shown, a CD 904 has a plurality of radiallyprinted lines 902 that have a twisting distortion. Without the twistingdistortion, these radially printed portions would appear straight. Thatis, ink would be dispensed along a radial line of the CD without thetwisting distortion effect. The resulting “twisting” distortion in theprinted image may be noticeable by the user or may be undetectable,depending on the complexity of the image source.

[0094] Dual conversion distortion is a fourth type of distortion, whichis the result of multiplicative errors from conversion processes (e.g.,converting the image source into a rectangular bitmap and converting therectangular bitmap into a polar bitmap). The dual conversion distortionresults in blurry edges on polygons or alphanumeric characters, forexample, since errors in the relative placement of each dot may occurwith each conversion of each image pixel into an associated printablepolar data point. The blurry edges may be acceptable in particularprinted images, such as a bitmap image of a photo. However, in certainapplications, the dual conversion distortion may result in anunacceptable printed image with unacceptably jagged, blurry text orshapes.

[0095]FIG. 10 is a diagrammatic representation of a character “A” thathas been converted into a plurality of rectangular dots 1004 andplurality of polar dots 1002. As shown, a first conversion distortion ispresent when the “A” is mapped onto a plurality of rectangular dots1004. For example, the “A” has uneven or “ragged” edges, wherein thedots do not align. This first distortion is caused by mapping each pixelof the data source to a closest rectangular dot position. This mappingmay not necessarily result in smooth edged polygons or alphanumericcharacters, for example. A second distortion occurs when the rectangulardots 1004 are mapped to polar dots 1002 within a rotated grid. Forexample, first rectangular dot 1004 a is mapped to a first polar dot1002 a.

[0096] Unfortunately, since the polar dots are in a radial pattern, asecond rectangular dot 1004 b must be mapped to a second polar dot(e.g., 1002 b) that is positioned lower or higher than the first polardot 1002 a. Thus, the polar “A” (without correcting for distortion)contains mapping errors inherent in calculating positions for therectangular dots 1004 of the rectangular “A”, as well as mapping errorsinherent in converting the rectangular dots 1004 into polar dots 1002.In sum, the “A” that is printed onto the rotating media may not appearas sharp or crisp as the image source “A”.

[0097] A number of techniques may be utilized to correct the abovedistortion problems that are associated with radial printing. Thefollowing Table 1 summarizes various techniques for correcting orimproving one or more of the above described distortion problems: TABLE1 Summary of Distortion Solutions Distortion Types Distortion Large Mis-Dual Solution Swath match Twisting Conversion High resolution X X XAngled printhead X X X Linear Motor X X X (Optical Feedback) Small stepson X X X Stepper Motor Greater angle X X X resolution Custom Driver XSlow RPM, X Constant linear X velocity Larger dot size X X Low radiusfill-in X Other ink shapes X Nozzle Firing X X Time Adjustment

[0098] For each possible distortion solution, an “X” in Table 1represents a potentially effective solution for one of the four abovedescribed distortion problems. One or more of these distortion solutionsmay be implemented, alone or in combination, in the present inventiondepending upon the particular application requirements.

[0099] One general solution for reducing the large swath, mismatch, anddual conversion distortions is to increase the print resolution. Thatis, in one embodiment of the present invention, the radial printer maybe configured to print with a relatively high resolution such that thelarge swath, mismatch, and dual conversion distortions are significantlyreduced or de-emphasized. For example, the mismatch distortion may bereduced with a relatively high resolution since the rectangular datapoints may be more accurately mapped to a larger pool of polar datapoints. By way of another example, the large swath and dual conversiondistortion may be undetectable at relatively high resolutions. That is,gaps between printed dots or areas may not be noticeable if the printeddots are spaced closer together.

[0100] An effective way to increase printing resolution is to increasethe capabilities of the head assembly, e.g., a higher dots per inch(dpi) capability. Another technique for increasing the resolution in onedirection is to permanently angle the print head such that more dots maybe printed per radius, for example. In another embodiment, a linearmotor with optical feedback to detect the print assembly's radialposition may be utilized to synthetically enhance resolution by anglingthe sensors that detect the print assembly's position. In other words,the angled sensors of the print assembly would allow a relatively highresolution for print assembly position. Another technique orconfiguration for increasing resolution is to implement a stepper motorthat is capable of moving the print assembly in relatively small stepsor increments.

[0101] Alternatively, the angular resolution may be increased to reducethe large swath, mismatch, and dual conversion distortions. For example,the angular resolution may be increased such that the image source isprinted on the media after one full rotation of the print head, and asecond rotation of the print head is then used to fill in any unwantedgaps caused by large swath, mismatch, or dual conversion distortion.That is, for the second rotation, the print head is offset from theprevious location of the print head during the first rotation. By way ofexample, if it is determined that one minute of arc is needed to printthe image source onto the media, a 30 second arc offset may be utilizedfor the second rotation for printing between the dots printed during thefirst rotation. This method is especially advantageous when there is alimit to how fast ink may be dispensed for a given rotation speed. Forexample, if ink can only be dispensed every 1 minute of arc, a secondprint rotation that is offset from a first print rotation allows forfiner resolution between dots or print areas.

[0102] An alternative to increasing the overall resolution is to onlyincrease the resolution for certain portions of the media. For example,a higher inner resolution may be utilized for inner radii to printwithin gaps that are the result of large swath distortion. Anothertechnique for reducing large swath distortion by filling in the gapsbetween inner radii is to print stripes or other shapes during innerradii printing or during all printing. For example, the printed stripeswould help to fill in the gaps from large swath distortion. Stripes maybe achieved by increasing the ink dispensement timing, for example.

[0103] A solution that may reduce the dual conversion distortion is toimplement a custom driver that is capable of accurately converting imageshapes into a polar data points. The custom driver would includealgorithms for converting known shapes (e.g., polygons) into a set ofpolar data points with substantially the same shape as the shape of theimage source. For example, a custom driver may convert a rectangle'scorners into polar data points and calculate positions for data pointswithin the remaining square's sides based on the corner's polar datapoints.

[0104] The present invention may also implement similar linearvelocities or relatively slow speeds for each position along the radiito reduce or eliminate the twisting distortion. The linear velocitiesmay be equal or merely similar enough such that the twisting distortionis undetectable by the human eye. If the platter rotated at a constantlinear velocity, for example, the time between the ink dispensement andthe ink contacting the media would not substantially vary with differentradii distances. That is, the ink would hit the media after apredictable and constant delay after ink dispensement. Thus, distancebetween the inner portions of the radii would not be substantiallydifferent than the outer portions of the radii, and the printed radiiwould not appear twisted.

[0105] In an alternative embodiment, printing areas may overlap on themedia. For example, the print dots may be sized such that each dotoverlaps with the adjacent printed dot. Overlapping print areas may beachieved by any suitable techniques or configurations of the presentinvention so as to reduce large swath and mismatch distortions. Forexample, the print assembly (and firing control) may be configured todispense ink in large enough quantities to cause overlap to occurbetween adjacent print areas.

[0106] To reduce large swath distortion and twisting distortion, avariable firing time may be implemented. That is, ink dispensement maybe carefully controlled such that large swath and/or twistingdistortions are undetectable. Large swath and/or twisting distortioneffects may be predicted for each dot or printing area of the media andthen used to calculate an appropriate ink firing delay such that eachdot is printed without any significant or detectable large swath and/ortwisting distortion. For example, the firing delay may be changed at aconstant rate as dots are printed along a radius to reduce the twistingdistortion. By way of another example, a nozzle firing delay may bechosen for inner dots such that gaps would not be detectable that weredue to large swath distortion.

[0107] The current invention has many advantages. The present inventionis capable of printing onto media having various sizes, shapes, andcompositions. That is, since the position of the head assembly 210 isbased on each polar based data point corresponding to an associated inkdispensement area on the platter 201, the head assembly 210 is capableof readily dispensing ink onto any media type that is positioned over anassociated ink dispensement area. For example, the present invention maybe used for printing onto a CD or CD label. The CD may be placed ontothe platter 201, and the platter is then rotated below the head assembly210. As the CD rotates below the head assembly 210, the print head 302efficiently dispenses ink onto the rotating CD. Additionally, thepresent invention may be used for printing on small sized media that areattached to the platter (e.g., by vacuum suctioning) and rotated belowthe print head 302.

[0108] The present invention also provides a simple mechanism forprinting. For example, the present invention implements rotationalmotion, which is achieved with inexpensive components, such as aflywheel device. Additionally, the head assembly may move in a slowsteady manner by being incrementally moved along a radial line relativeto the rotating media. That is, the present invention has the advantageof efficiently utilizing the substantially continuous rotationalmovement of the media for printing, as compared with conventionalsystems that stop printing while the media is moved to a new positionbelow the head assembly.

[0109] Additionally, the platter 201 provides a relatively stable basefor the media 220. In other words, the media 220 is affixed to a stablerotating platter 201 such that a particular point on the media 220 maybe repeatedly rotated to the same position below the head assembly 210.Thus, the relative stability of the media 220 allows the head assembly210 to accurately reprint onto the same location on the media 220. Forexample, for color printing, more than one color may be printed onto oneink dispensement area on the media 220. Additionally, the relativestability of the media 220 allows the head assembly 210 to accuratelyprint in sectors, for example, with few registration problems. In sum,the relative stability of the media 220 allows for increased printingefficiency and accuracy.

[0110] Additionally, if the platter 201 of the present invention isconfigured to have a holding device that affixes a plurality of media220 onto the platter 201 at one time and a media feeding device thatfeeds a plurality of media onto the holding device, the presentinvention will be capable of high speed printing.

[0111] While this invention has been described in terms of severalpreferred embodiments, there are alterations, permutations, andequivalents which fall within the scope of this invention. For example,multiple print heads may be implemented and placed at multiple radialand axial positions. It is therefore intended that the followingappended claims be interpreted as including all such alterations,permutations, and equivalents as fall within the true spirit and scopeof the present invention.

What is claimed is:
 1. A radial printing system for receiving an imagesource representative of an image to be printed on a rotating media, theimage source having a plurality of image points expressed in Cartesiancoordinates, the system comprising: a computer imaging system configuredto convert the plurality of image points expressed in Cartesiancoordinates into a plurality of polar image points expressed in polarcoordinates, wherein each polar point corresponds to a location on themedia, wherein the computer imaging system is further configured todetermine a first ink dispensement time for a first radius and aselected angle of the media and to determine a second ink dispensementtime for a second radius and the selected angle; and a head assemblycoupled to the computer imaging system for outputting a first ink objectalong the first radius of the rotating media and outputting a second inkobject along the second radius, wherein the head assembly is furtherconfigured to output the first ink object along the first radius at thefirst ink dispensement time and to output the second ink object alongthe second radius at the second ink dispensement time, wherein the firstand second ink dispensement times are determined such that the first andsecond ink object output at the first and second ink dispensement times,respectively, hit the media at the selected angle on the media andwherein the first radius differs from the second radius and the firstink dispensement differs from the second ink dispensement time.
 2. Theradial printing system of 1, further comprising: a rotation motorconfigured to rotate the media and to provide rotation position datathat indicates a current rotation position of the rotation motor; and aservo system configured to receive the rotation position data from therotation motor and to control the rotation motor responsive to therotation position data.
 3. The radial printing system recited in claim 2, wherein the head assembly includes a print head that is angled toincrease radial resolution.
 4. The radial printing system recited inclaim 2 , further comprising a synchronization system coupled with theimaging system and the servo system, the synchronization system beingconfigured to ensure that the head assembly prints at a specifiedposition on the rotating media.
 5. The radial printing system recited inclaim 1 , further comprising a platter for supporting the rotatingmedia, wherein the platter includes a holding device for affixing themedia onto the platter during printing, wherein the holding device isfurther configured to attach a plurality of media at one time to theplatter.
 6. The radial printing system recited in claim 5 , wherein theimaging system is further configured to print the representation of theimage onto each of the plurality of media.
 7. The radial printing systemrecited in claim 6 , further comprising a media feeding device forhandling a plurality of media.
 8. The radial printing system recited inclaim 1 , wherein the head assembly implements a technology type fromone of a group consisting of ink jet, laser, pen, dye-sublimation,thermal transfer, and electrostatic technologies.
 9. The radial printingsystem recited in claim 1 , wherein the head assembly is furtherconfigured to facilitate a chemical process wherein a first chemical isprinted onto the media whereby the first chemical reacts with the mediaand forms a second chemical on the media.
 10. The radial printing systemrecited in claim 2 , wherein the servo system is further configured toprovide a substantially constant linear velocity.
 11. The radialprinting system recited in claim 1 , wherein the head assembly includesa curing bar for curing ink that is printed onto the rotating media. 12.The radial printing system recited in claim 1 , wherein the headassembly includes a drying bar for drying ink that is printed onto therotating media.
 13. The radial printing system recited in claim 1 ,wherein the head assembly includes an optical reader for retrievingoptical information from the media.
 14. The radial printing systemrecited in claim 1 , further comprising a platter for supporting therotating media, wherein the head assembly includes an optical reader forobtaining optical information from the platter.
 15. The radial printingsystem recited in claim 14 wherein the obtained optical informationincludes a zero angle indicator for the platter, the zero angleindicator being output to the imaging system to determine an origin ofthe platter.
 16. The radial printing system recited in claim 14 ,wherein the obtained optical information represents a first printedimage on the media that is output to the imaging system to be used tooverlay a second printed image on the media.
 17. The radial printingsystem recited in claim 2 , wherein the servo system is furtherconfigured to provide a substantially constant angular velocity
 18. Theradial printing system recited in claim 2 , further comprising a platterfor supporting the rotating media, wherein the platter is configured toprovide platter position data that indicates a current platter positionof the platter relative to the head assembly, the servo system alsobeing configured to receive the platter position data from the platterand to control radial movement of the platter relative to the media inresponse to the platter position data.
 19. The radial printing systemrecited in claim 2 , further comprising a platter for supporting therotating media, wherein the head assembly is further configured to movevertically relative to the platter and to provide vertical position datathat indicates a current vertical position of the head assembly, theservo system also being configured to receive the vertical position datafrom the head assembly and to control vertical movement of the headassembly in response to the vertical position data.
 20. The radialprinting system recited in claim 1 , further comprising a platter forsupporting the rotating media, wherein the platter is configured suchthat the rotating media may be in the form of one from the groupconsisting of a compact disk label and a compact disk.
 21. The radialprinting system recited in claim 1 , further comprising a platter forsupporting the rotating media, wherein the platter is configured suchthat the rotating media may be formed from a relatively inflexiblematerial.
 22. The radial printing system recited in claim 1 , whereinthe imaging system is configured to reduce printing distortion of onefrom a group consisting of large swath, mismatch, twisting, and dualconversion distortion.
 23. The radial printing system recited in claim22 , wherein the imaging system is configured to fills in gaps caused byprinting distortion.
 24. The radial printing system recited in claim 23, wherein the imaging system fills in gaps caused by printing distortionby printing extra dots that are not associated with the image source.25. The radial printing system recited in claim 23 , wherein the imagingsystem fill in gaps caused by printing distortion by printing the imagesource onto overlapping ink dispensement areas.
 26. A method forreproducing an image on a rotating media, comprising: determining afirst ink dispensement time for a first radius and a selected angle ofthe media; determining a second ink dispensement time for a secondradius and the selected angle; printing a first ink object along thefirst radius; and printing a second ink object along the second radius,wherein the first ink object is printed along the first radius at thefirst ink dispensement time and the second ink object is printed alongthe second radius at the second ink dispensement time and wherein thefirst and second ink dispensement times are determined such that thefirst and second ink object printed at the first and second inkdispensement times, respectively, hit the media at the selected angle onthe media and wherein the first radius differs from the second radiusand the first ink dispensement differs from the second ink dispensementtime.